Rethinking Speech Representation Aggregation in Speech Enhancement: A Phonetic Mutual Information Perspective

Fuente: arXiv
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Autores principales: Han, Seungu, Lee, Sungho, Lee, Kyogu
Formato: Preprint
Publicado: 2026
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author Han, Seungu
Lee, Sungho
Lee, Kyogu
author_facet Han, Seungu
Lee, Sungho
Lee, Kyogu
contents Recent speech enhancement (SE) models increasingly leverage self-supervised learning (SSL) representations for their rich semantic information. Typically, intermediate features are aggregated into a single representation via a lightweight adaptation module. However, most SSL models are not trained for noise robustness, which can lead to corrupted semantic representations. Moreover, the adaptation module is trained jointly with the SE model, potentially prioritizing acoustic details over semantic information, contradicting the original purpose. To address this issue, we first analyze the behavior of SSL models on noisy speech from an information-theoretic perspective. Specifically, we measure the mutual information (MI) between the corrupted SSL representations and the corresponding phoneme labels, focusing on preservation of linguistic contents. Building upon this analysis, we introduce the linguistic aggregation layer, which is pre-trained to maximize MI with phoneme labels (with optional dynamic aggregation) and then frozen during SE training. Experiments show that this decoupled approach improves Word Error Rate (WER) over jointly optimized baselines, demonstrating the benefit of explicitly aligning the adaptation module with linguistic contents.
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id arxiv_https___arxiv_org_abs_2601_22480
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publishDate 2026
record_format arxiv
spellingShingle Rethinking Speech Representation Aggregation in Speech Enhancement: A Phonetic Mutual Information Perspective
Han, Seungu
Lee, Sungho
Lee, Kyogu
Sound
Audio and Speech Processing
Recent speech enhancement (SE) models increasingly leverage self-supervised learning (SSL) representations for their rich semantic information. Typically, intermediate features are aggregated into a single representation via a lightweight adaptation module. However, most SSL models are not trained for noise robustness, which can lead to corrupted semantic representations. Moreover, the adaptation module is trained jointly with the SE model, potentially prioritizing acoustic details over semantic information, contradicting the original purpose. To address this issue, we first analyze the behavior of SSL models on noisy speech from an information-theoretic perspective. Specifically, we measure the mutual information (MI) between the corrupted SSL representations and the corresponding phoneme labels, focusing on preservation of linguistic contents. Building upon this analysis, we introduce the linguistic aggregation layer, which is pre-trained to maximize MI with phoneme labels (with optional dynamic aggregation) and then frozen during SE training. Experiments show that this decoupled approach improves Word Error Rate (WER) over jointly optimized baselines, demonstrating the benefit of explicitly aligning the adaptation module with linguistic contents.
title Rethinking Speech Representation Aggregation in Speech Enhancement: A Phonetic Mutual Information Perspective
topic Sound
Audio and Speech Processing
url https://arxiv.org/abs/2601.22480